Catalyst 8.10 adds the support of Geometry Instancing in OpenGL via the extension GL_ARB_draw_instanced. But currently this extension seems to have a bug (on the upcoming GPU Caps Viewer 1.6.0, the geometry instancing demo fails to start due to a vertex shader linking problem). NVIDIA and S3 support for long time geometry instancing via GL_EXT_draw_instanced but they do not expose GL_ARB_draw_instanced. So be sure to add a double check of GL_EXT_draw_instanced or GL_ARB_draw_instanced in your initialization code to use GI feature. Catalyst 8.10 also fixes a bug in vertex texture fetching so vertex displacement mapping is now possible on Radeon graphics cards.

Catalyst 8.10, like Catalyst 8.8 and 8.9, still slow down the GPU when FurMark is detected (see here and here for more detail).

Update (2008-10-16)
With the latest Catalyst 8.11 RC1, the geometry instancing demo is now fully operational. What I said about GL_ARB_draw_instanced and GL_EXT_draw_instanced is also valid at the functions level: